Synthesis of Optically Active α-Hydroxy Carbonyl Compounds by the Catalytic, Enantioselective Oxidation of Silyl Enol Ethers and Ketene Acetals with (Salen)manganese(III) Complexes
作者:Waldemar Adam、Rainer T. Fell、Veit R. Stegmann、Chantu R. Saha-Möller
DOI:10.1021/ja9726668
日期:1998.2.1
A set of silyl enol ethers and ketene acetals 1a−h with α- and/or β-phenyl as well as alkyl substituents of different steric bulk has been submitted to the enantioselective catalytic oxidation by chiral (salen)MnIII complexes 3. Highest conversions and best enantioselectivities have been obtained with bleach rather than iodosobenzene as oxygen source for the active oxo−metal species. With regard to
Optically active α-hydroxy ketones 4 have been prepared in high enantioselectivity by the catalytic, enantioselective oxidation of easily available and stable (E)-enol phosphates 2 by (salen) Mn(III) complex.
Stereoselective Synthesis of Optically Active α-Hydroxy Ketones and <i>a</i><i>nti</i>-1,2-Diols via Asymmetric Transfer Hydrogenation of Unsymmetrically Substituted 1,2-Diketones
作者:Takashi Koike、Kunihiko Murata、Takao Ikariya
DOI:10.1021/ol0002572
日期:2000.11.1
[reaction: see text] A well-defined chiral Ru catalyst RuCl(N-(p-toluenesulfonyl)-1, 2-diphenylethylenediamine)(eta(6)-arene) effectively promotes asymmetric transfer hydrogenation of 1-aryl-1,2-propanedione with HCOOH/N(C(2)H(5))(3), leading preferentially to opticallyactive 1-aryl-2-hydroxy-1-propanone with up to 99% ee and 89% yield at 10 degrees C. The reaction at 40 degrees C gives anti-1-aryl-1
The catalytic asymmetric synthesis of chiral 2‐hydroxy ketones by using different thiaminediphosphatedependent enzymes, namely benzaldehydelyase from Pseudomonas fluorescens (PfBAL), a variant of benzoylformate decarboxylase from Pseudomonas putida (PpBFD‐L461A), branched‐chain 2‐keto acid decarboxylase from Lactococcus lactis (LlKdcA) and a variant of pyruvate decarboxylase from Acetobacter pasteurianus
Asymmetric α-hydroxy ketone synthesis by direct ketone oxidation using a bimetallic palladium(II) complex
作者:Othman A. Hamed、Arab El-Qisairi、Hanan Qaseer、Emad M. Hamed、Patrick M. Henry、Daniel P. Becker
DOI:10.1016/j.tetlet.2012.03.066
日期:2012.5
The oxidation of ketones by a chiral bimetallic palladium(II) complex in the presence of CuCl2 in THF–water solvents gave an enantioselective synthesis of α-hydroxyketones in catalytic oxidation utilizing an atmosphere of oxygen. The ee’s ranged from 61% to 92%. The reaction was accelerated by addition of strong acid that presumably increases the rate of enolization.